The Pentagon has unveiled its “roadmap” for future generation of unmanned vehicles, offering a glimpse into more sophisticated and lethal drones over the next 25 years.

The Unmanned Systems Integrated Roadmap, released last week, marks out several milestones which will see the US armed forces increasingly reliant on unmanned aircraft as well as water and ground-based robots in the coming decades.

The Department of Defense is looking to enhance the precision navigation, swarming munitions and increased autonomy of future drones, according to the document.

The satellite signals behind the Global Positioning System (GPS) which unmanned aircraft currently depend on for navigation are often weak and easily jammed. The Pentagon therefore has tasked the Defense Advanced Research Projects Agency (DARPA) to address the problem and work on the so-called pinpoint inertial guidance systems that are jam-proof.

The Pentagon also wants to see drone-carried munitions deliver much more powerful explosions through the use of “energetic nano-particles” as drone ammunition.

Even though drone-based missions have proven significantly cheaper in a monetary sense compared to more traditional manpower intensive missions, the Pentagon says they are still expensive and seeks to slash costs even further by developing more autonomous robots and offloading as many human tasks as possible onto machines.

The “roadmap” also references “nano” drones, insect-sized robots designed for land and air, as well as “robotic wingmen” to provide unmanned help to ground-based troops.

While drones in the air are more widely used and familiar, the document says ground-based robots too “have proven their worth in Iraq and Afghanistan across a spectrum of mission areas.”

The “roadmap” also includes a plan to develop water-based drones for mine-hunting and maritime security.